After few days of testing:
Dram timing modes were set to 3-3/5-5.
Under stress test with Prime95 the memory voltage drops a lot to 1,66v. This stress is similar to any 3d engine especially when combined with video playback.
With those voltages system survived 7 hours in 35 °c ambient temperature, 60°c on NB, 70°c on CPU.
This chipset is beast. Therefore I decided to upgrade also my PSU. I removed the great Seasonic 500W and used Corsair 650watt PSU again. 5v and 12v rails stabilized a bit. 3.3v now shows 3.08v which is still not the best, but better than 3,02v with seasonic psu.